Diagnostic Considerations

The most common type of arthrogryposis seen in clinical practice and constitutes about one third of cases

The incidence is about 1 in 10,000 live births

Amyoplasia is a sporadic condition and has not been observed in siblings or offspring

The pathogenesis is thought to involve impaired blood circulation to the fetus early in pregnancy; hypotension and hypoxia damage the anterior horn cells, resulting in a lack or underdevelopment of muscle tissue, with fatty or connective tissue replacement

Symmetrical limb involvement is noted

The distinct positioning of the body includes internally rotated and adducted shoulders; fixed, extended elbows; pronated forearms; and flexed wrists and fingers

A severe talipes equinovarus deformity with either flexed or extended knees may be present

Hips may be flexed and externally rotated or extended and subluxated or dislocated

Characteristic midline facial hemangioma is often noted

Intelligence is normal

The natural history of untreated amyoplasia is largely undocumented and unknown. However, a study documented a 94% rate of survival for individuals with amyoplasia at 20 years.
[4] Without treatment, the ambulatory and functional potential of afflicted individuals is poor.

Distal arthrogryposes

These involve the distal joints and include the following types and subtypes (all have autosomal dominant inheritance with reduced penetrance and variable expressivity)
[14] :

This is likely to be confused with arthrogryposis but includes symphalangism (ie, fusion of phalanges), coalition (ie, fusion of the carpals and tarsal bones), and synostosis (ie, fusion of long bones).

Contractural arachnodactyly (Beals syndrome; OMIM 121050)

This is an autosomal dominant disorder. It is characterized by joint contractures; a long, thin body build; and crumpling ears. It usually lacks the cardiovascular and ocular abnormalities of Marfan syndrome.

The autosomal dominant type is characterized by multiple pterygia with or without MR

Multiple pterygium syndrome, characterized by pterygia with flexion contractures, scoliosis, and cleft palate, has been reported in several families and is associated with malignant hyperthermia

Multiple pterygium syndrome, Escobar type is characterized by webbing of the neck that increases with age, webbing of the knees and elbows that develops before adolescence, multiple joint contractures, and lumbar lordosis
[17]

This is an autosomal dominant disorder characterized by popliteal webs, cleft lip or palate, webs in the mouth, and unusual nails.

Lethal popliteal pterygium syndrome (OMIM 263650)

This is also known as Bartsocas-Papas syndrome and is an autosomal recessive disorder characterized by severe webs across the knee. In the newborn period, it is associated with facial clefting and fused digits (synostosis of the hand and foot bones). It is usually lethal.

Freeman-Sheldon syndrome (OMIM 193700)

This is also known as whistling face syndrome and is an autosomal dominant disorder. It is characterized by a masklike face with a small mouth, giving a whistling face appearance; deep-set eyes; small nose with a broad nasal bridge; epicanthal folds; strabismus; high arched palate; small tongue; an H-shaped cutaneous dimpling on the chin; flexion of fingers; equinovarus feet with contracted toes; kyphosis; scoliosis; and other anomalies.
[23]

The hands of a patient with contractural arachnodactyly (Beals syndrome). Note the long, thin fingers with interphalangeal joint contractures.

A girl with an autosomal recessive type of multiple pterygium syndrome. Note the multiple joint contractures at the knees with marked pterygia, including intercrural webbing, affecting her stance and ambulation.

A mother and child both affected with trismus pseudocamptodactyly. Note the small mouth (with limited ability to open) and flexion contractures of fingers on dorsiflexion.

An infant with a lethal type of multiple pterygium syndrome. Note multiple joint contractures with marked pterygia and a cystic hygroma on the posterior aspect of the head and the neck.

The photograph on the left shows an infant with fetal akinesia. Note depressed nasal bridge, micrognathia, flexion contractures of elbows, bilateral clubhands, and arthrogryposis of fingers. The radiograph on the right shows an infant with fetal akinesia. Note gracile ribs; thin, long bones with multiple fractures at mid diaphyses of the humeri, distal diaphyses of the femora, and proximal diaphyses of both tibiae and left fibula; and clubhands.

An infant with Pena-Shokeir syndrome. Note characteristic facies (ocular hypertelorism; short nose with depressed bridge; small and markedly recessed jaw; low-set, malformed ears), short neck, mild contracture at the hip, moderate contractures at elbows and knees, severe ankle contractures, and camptodactyly with ulnar deviation of the hands.